Vertebral body replacement devices are indicated to provide anterior column support following a corpectomy, vertebrectomy, or spondylectomy as a result of trauma to the spine, removal of tumor material from the spinal column, or to correct spinal deformity. Surgeons typically utilize a number of different devices to provide this anterior column support, including structural bone struts made from auto- or allograft tissue, structural titanium mesh cages, expandable titanium devices, and makeshift constructs using polymethylmethacrylate (PMMA) cement and other common surgical devices, such as chest tubes, Steinmann pins, bone screws, etc., to reinforce and/or contain the cement.
In cases in which it is desirable to address the patient's pathology from a posterior or posterolateral approach, the patient's neurological structures, such as the spinal cord, cauda equina, and exiting nerve roots, limit access to the corpectomy defect, limiting the use of many of the currently available devices or forcing the surgeon to use an implant size or configuration that is less than optimal. In such cases, surgeons often opt to use PMMA to fill the defect size since it can be injected through a narrow channel and can easily conform to the individual patient's anatomy. Often, the PMMA is supplemented with another device to reinforce and/or contain the cement. However, cement constructs are difficult to revise, the PMMA allows a limited working time window, and the PMMA undergoes an exothermic curing reaction that can damage surrounding tissues. Further, there is little or no fusion potential when using these constructs and their application is typically limited to patients with a low life expectancy, e.g., tumor patients.